Quantum Dots for Explosive Detection in Air-Two Complimentary Approaches

With the threatening increase in explosive-based terrorism against civil populations, the development of new devices capable of a rapid and cost-effective detection of hidden explosives has become a worldwide priority. Recently, semiconductor quantum dots have demonstrated great potential as luminescent probes for trace explosive detection. However, the growing interest in this technology and its potentiality is not accompanied by its widespread use in practical applications and in operating environments since most of the proposed devices still consist of lab-based procedures not amenable for field operation. This work explores and compares two alternative ways of employing quantum dots as sensing material to build simple, compact, and reusable devices for vapor explosive detection, beyond their typical use as fluorescent probes in solution. First, a high-performance chemiresistive sensor whose electrical resistance changes proportionally to the target gas concentration is proposed. Then, we present an optical system based on the solid-state photoluminescence of quantum dots cast on a silicon substrate. Easy fabrication, portability, low-cost, high sensitivity, and reusability make both the reported devices quite promising not only for laboratory-scale testing but also for practical applications on the field.